Attack of the POOP Hawk as we call it here. I'm not a big fan of these birds but I think this shot works perfectly for stock photo. Superb capture on this one.
I like the position of the gull and the way you captured the action in this shot but if this were my image there are a couple of things I would change. First, I think I would give the bird a little more room in front and below for it to fly into. I also am not totally thrilled about the background. I am guessing that you were trying for a white background but the picture just appears (to me) to be just too overexposed and a bit too much detail has been lost. I think this image would be really great if it were in front of a plain background that wasn’t so bright.